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Critical behaviour and magnetocaloric effect of nano crystalline La0.67Ca0.33Mn1−xFexO3 (x = 0.05, 0.2) synthesized by nebulized spray pyrolysis

Nisha, P. and Savitha Pillai, S. and Darbandi, Azad and Varma, Manoj Raama and Suresh, K. G. and Hahn, Horst (2012):
Critical behaviour and magnetocaloric effect of nano crystalline La0.67Ca0.33Mn1−xFexO3 (x = 0.05, 0.2) synthesized by nebulized spray pyrolysis.
In: Materials Chemistry and Physics, 136 (1), Elsevier Science Publishing, pp. 66-74, ISSN 02540584,
[Online-Edition: http://dx.doi.org/10.1016/j.matchemphys.2012.06.029],
[Article]

Abstract

The structure, critical exponents and magnetocaloric effect (MCE) of Nebulized Spray Pyrolysis (NSP) synthesized nano crystalline La0.67Ca0.33Mn1−xFexO3 (x = 0.05, 0.2) were investigated. The Reitveld refinement of XRD patterns show that the samples adopt an orthorhombic structure with Pnma space group. TEM inspection reveals that the average particle size is about 15 nm and 42 nm for NSP synthesized LCMFe0.05 and LCMFe0.2 samples respectively. The temperature and field dependent magnetization studies reveal the superparamagnetic state of La0.67Ca0.33Mn0.95Fe0.05O3 and spin-glass-like state of La0.67Ca0.33Mn0.8Fe0.2O3. The critical behaviour at the transition region studied using modified Arrott plot provides a second order nature of phase transition for both samples. The magnetocaloric studies show the maximum value of magnetic entropy change (ΔSmax) is in the range 2.3 J kg−1 K−1 at 158 K for LCMFe0.05 and 0.3 J kg−1 K at 92 K for LCMFe0.2 respectively at 5 T field. The field dependence of the magnetic entropy changes are also analysed, which show a power law dependence (ΔSM ∞ Hn, n = 0.72 (2)) at transition temperature, TC = 162 K for LCMFe0.05 and n = 1.11(3) at 92 K for LCMFe0.2.

Item Type: Article
Erschienen: 2012
Creators: Nisha, P. and Savitha Pillai, S. and Darbandi, Azad and Varma, Manoj Raama and Suresh, K. G. and Hahn, Horst
Title: Critical behaviour and magnetocaloric effect of nano crystalline La0.67Ca0.33Mn1−xFexO3 (x = 0.05, 0.2) synthesized by nebulized spray pyrolysis
Language: English
Abstract:

The structure, critical exponents and magnetocaloric effect (MCE) of Nebulized Spray Pyrolysis (NSP) synthesized nano crystalline La0.67Ca0.33Mn1−xFexO3 (x = 0.05, 0.2) were investigated. The Reitveld refinement of XRD patterns show that the samples adopt an orthorhombic structure with Pnma space group. TEM inspection reveals that the average particle size is about 15 nm and 42 nm for NSP synthesized LCMFe0.05 and LCMFe0.2 samples respectively. The temperature and field dependent magnetization studies reveal the superparamagnetic state of La0.67Ca0.33Mn0.95Fe0.05O3 and spin-glass-like state of La0.67Ca0.33Mn0.8Fe0.2O3. The critical behaviour at the transition region studied using modified Arrott plot provides a second order nature of phase transition for both samples. The magnetocaloric studies show the maximum value of magnetic entropy change (ΔSmax) is in the range 2.3 J kg−1 K−1 at 158 K for LCMFe0.05 and 0.3 J kg−1 K at 92 K for LCMFe0.2 respectively at 5 T field. The field dependence of the magnetic entropy changes are also analysed, which show a power law dependence (ΔSM ∞ Hn, n = 0.72 (2)) at transition temperature, TC = 162 K for LCMFe0.05 and n = 1.11(3) at 92 K for LCMFe0.2.

Journal or Publication Title: Materials Chemistry and Physics
Volume: 136
Number: 1
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Magnetic materials, Chemical synthesis, Oxides, Electron microscopy (STEM, TEM and SEM), Critical phenomena, Magnetic properties
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Joint Research Laboratory Nanomaterials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 17 Jun 2014 11:11
Official URL: http://dx.doi.org/10.1016/j.matchemphys.2012.06.029
Identification Number: doi:10.1016/j.matchemphys.2012.06.029
Funders: Dr. Manoj Raama Varma would like to thank German Academic Exchange Service DAAD for the support to his visit INT, Karlsrhue., Nisha and Dr. Manoj Raama Varma would like to thank Department of Science and Technology, Government of India for Providing HRTEM facility at NIIST, Trivandrum Defence Research Development Organization, Government of India for supporting the project.
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